Book - The development of the frog's egg (1897)
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Morgan TH. The development of the frog's egg: an introduction to experimental embryology. (1897) The Macmillan Co. London.
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| This 1897 textbook by Thomas Morgan Hunt (1866-1945) is an extensive description of early frog development. Morgan was one of the eearly founders of embryology in the Category:USA.
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The Development of the Frog's Egg
An Introduction to Experimental Embryology
Professor Of Biology, Bryn Mawr College
The Macmillan Company
London: Macmillan & Co., Ltd. 1897
Preface
The development of the frog's egg was first made known through the studies of Swammerdam, Spallanzani, Rusconi, and von Baer. Their work laid the basis for all later research. More recently the experiments of Pfluger and of Roux on this egg have turned the attention of embryologists to the study of development from an experimental standpoint. Owing to the ease with which the frog's egg can be obtained, and its tenacity of life in a confined space, as well as its suitability for experimental work, it is an admirable subject with which to begin the study of vertebrate development.
In the following pages an attempt is made to bring together the most important results of studies of the development of the frog's egg. I have attempted to give a continuous account of the development, as far as that is possible, from the time when the egg is forming to the moment when the young tadpole issues from the jelly-membranes. Especial weight has been laid on the results of experimental work, in the belief that the evidence from this source is the most instructive for an interpretation of the development. The evidence from the study of the normal development has, however, not been neglected, and wherever it has been possible I have attempted to combine the results of experiment and of observation, with the hope of more fully elucidating the changes that take place. Occasionally departures have been made from the immediate subject in hand in order to consider the results of other work having a close bearing on the problem under discussion. I have done this in the hope of pointing out more definite conclusions than could be drawn from the evidence of the frog's egg alone.
In treating the general problems of development, I have tried to keep as near to the evidence as possible. I have intentionally avoided at times the discussion of the more theoretical problems arising from the experiment, for it seems to me that such discussions are out of place in a volume of this sort. Only the early stages of the development have been considered, because almost all of the experimental work on the frog's egg has been done on the early stages, and also because I am more fam,iliar with the development and with the experiments of this period. Moreover, the later stages have been recently most admirably described by Marshall in his Vertebrate Embryology.
A few words of personal explanation may be added. For several years I have been collecting the material for the present volume, but as the literature is so extensive and as I have had other work to do first, I made but slow progress. In the summer of 1893 I set seriously to work, and owe much to the admirable facilities offered by the University of Berlin. I take pleasure in acknowledging my indebtedness to Geheimrath Professor Fr. E. Schulze for many privileges and kindnesses extended to me in Berlin. The work Avas continued irregularly during the winter of 1893-1894 while enjoying the oppor.tunities of the Stazione Zoologica in Naples. During the winter of 1894-1895 the material was brought together and in the summer of 1896 at Zurich the manuscript was almost completed. I gladly take this opportunity to thank Professor Arnold Lang for many courtesies extended to me during two visits to Ziirich. Dr. Driesch has most kindly looked over some of the chapters, and has made many valuable suggestions. Dr. H. H. Field has also examined a part of the manuscript and helped me in several directions. To Professor E. B. Wilson I am under heavy obligations, and owe much to his valuable suggestions and corrections. To Dr. H. Randolph I owe a debt of gratitude for kindly advice and criticism. I am also greatly indebted to Professor Joseph W. Warren and to Professor E. A. Andrews for advice in connection with the revision of the proof.
Contents
- Chapter I The Formation of the Sex-cells Spermatogenesis. " Direct " Division of the Germ-cells. Oogenesis. Comparison of Spermatogenesis with Oogenesis.
- Chapter II Polar Bodies and Fertilization Extrusion of the First Polar Body and Egg-laying. The Jelly of the Egg, and the Second Polar Body. Entrance of Spermatozoon and Copulation of Pronuclei.
- Chapter III Experiments in Cross-fertilization Experiments of Pflūger and of Born on Frogs' Eggs. Experiments on Other Forms. Experiments of Rauber and of Boveri.
- Chapter IV Cleavage of the Egg Normal Cleavage. Correspondence of the First Cleavage-plane and the Median-plane of the Embryo. Roux's Experiments with Oil-drops. Historical Account of the Cleavage of the Frog's Egg.
- Chapter V Early Development of the Embryo The Blastopore. External Changes after the Closure of the Blastopore.
- Chapter VI Formation of the Germ-layers His's Experiments with Elastic Plates. The Formation of the Embryo by Concrescence. The Formation of the Archenteron. The Overgrowth of the Blastoporic Rim. The Origin of the Mesoderm. Different Accounts of the Origin of the Archenteron and Mesoderm. Later Development of the Mesoderm and Origin of the Notochord.
- Chapter VII The Production of Abnormal Embryos with Spina Bifida
- Chapter VIII Pfluger's Experiments on the Frog's Egg The Effect of Gravity on the Direction of the Cleavage. The Relation of the Planes of Cleavage to the Axes of the Embryo. Conclusions from the Experiments.
- Chapter IX Experiments of Born and of Roux Changes that take Place in the Interior of the Egg after Rotation. The Cleavage of the Egg in a Centrifugal Machine.
- Chapter X Modification of Cleavage by Compression of the Egg Effect of Compressing the Segmenting Egg between Parallel Plates. Conclusions from the Experiments. The Distribution of the Nuclei in the Compressed Egg.
- Chapter XI The Effect of Injuring One of the First Two Blastomeres Roux's Experiment of " Killing " One of the First Two Blastomeres. Further Experiments by Others (Hertwig, Endres and "Walter, Schultze, Wetzel, Morgan).
- Chapter XII Interpretations of the Experiments and Conclusions
Roux's Mosaic Theory of Development. Theory of Driesch and of Hertwig of the Equivalency of the Early Blastomeres. Roux's Subsidiary Hypothesis. Experiments on Other Forms. General Conclusions.
- Chapter XIII Organs from the Endoderm The Closure of the Blastopore, and the Formation of the Neuren teric Canal. The Digestive Tract and the Gill-slits.
- Chapter XIV Organs from the Mesoderm The Mesodermic Somites. The Heart and Blood-vessels. The Pronephros.
- Chapter XV Organs from the Ectoderm The Central Nervous System. The Eyes. The Ears. The Nerves. The Appearance of Cilia on the Surface of the Embryo.
- Chapter XVI Effects of Temperature and of Light on Development
- Literature
- Figures
Introduction
The eggs of most of our species of frogs are laid in the spring. In some cases they are set free almost immediately on the emergence of the frogs from their winter sleep ; in other cases the eggs are not laid until some weeks or even months after the frogs have awakened. In almost every instance the eggs are deposited in water and usually in quiet pools or ponds, or in protected bays along streams where the water has backed up and has come to rest. Sometimes the bunches of eggs are stuck to sticks, grass, submerged sedge, or even to stones ; in other cases the bunches are not fastened.
The copulation precedes and lasts through the laying-period ; a single male fertilizing all the eggs laid by one female. The sperm pours out of the cloaca of the male at the moment when the eggs pass out of the female.
Both the male and the female sexual products, the eggs and spermatozoa, are ripened during the summer and autumn of the year preceding the deposition of the eggs, — at least this is the more usual process. The origin of these sexual cells must first be studied in order to more fully understand their relation to each other, and the part they play in the subsequent development.
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Morgan TH. The development of the frog's egg: an introduction to experimental embryology. (1897) The Macmillan Co. London.
Cite this page: Hill, M.A. (2024, April 25) Embryology Book - The development of the frog's egg (1897). Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Book_-_The_development_of_the_frog%27s_egg_(1897)
- © Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G
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